This earthcache is located in lovely Shenandoah, VA.
Iron Ores are rocks and minerals from which metallic iron
can be economically extracted. The ores are usually rich in iron
oxides and vary in color from dark grey, bright yellow, deep
purple, to rusty red. The iron itself is usually found in the form
of magnetite (Fe3O4), hematite (Fe2O3), goethite (FeO(OH)),
limonite (FeO(OH).n(H2O)) or siderite (FeCO3). Hematite is also
known as "natural ore". The name refers to the early years of
mining, when certain hematite ores contained 66% iron and could be
fed directly into iron making blast furnaces. Iron ore is the raw
material used to make pig iron, which is one of the main raw
materials to make steel. 98% of the mined iron ore is used to make
steel.[1] Indeed, it has been argued that iron ore is "more
integral to the global economy than any other commodity, except
perhaps oil.”[2]
There are three different ways to identify sources of iron.
Banded iron formations (BIF) are metamorphosed sedimentary
rocks composed predominantly of thinly bedded iron minerals and
silica (as quartz). Magmatic magnetite ore deposits,
Occasionally granite and ultrapotassic igneous rocks, segregate
magnetite crystals and form masses of magnetite suitable for
economic concentration. A few iron ore deposits are formed from
volcanic flows containing significant accumulations of magnetite
phenocrysts. Hematite iron is typically rarer than magnetite
bearing BIF or other rocks which form its main source or protolith
rock, but it is considerably cheaper to process as it generally
does not require beneficiation due to its higher iron content.
The Big Gem site was once the location of one of the most
prominent iron production facilities in the south. Locals called
the large furnace “Big Gem” because of the brilliant
glow that radiated out of the ravine where the foundry and iron
facility was located. With the exception of its brief use as a
municipal landfill in the 1950’s, the Big Gem site remained
idle from the 1890’s to 1998. Graduate students at James
Madison University identified EPA’s Brownfields Pilot program
as a potential fit for Shenandoah, leading to an EPA Assessment
Pilot Award. More information can be found at
Big Gem Park
The iron industry played a vital role in the industrialization
of the United States and in the development of the U.S.economy and
society. Much of the early history of the iron industry took place
in Virginia. The remains of 11 iron furnaces and nearby mines in
the George Washington and Jefferson National Forests in Virginia
and West Virginia are silent reminders of a time when iron mines
and furnaces operated along a belt that extended through the
Appalachian Mountains from New York State to Alabama.
Why was iron found and exploited along this belt?
Iron mines and furnaces were operated in the long,
northeast-trending belt of the Appalachians because two key
ingredients of the iron industry iron ore and limestone (to remove
impurities and promote fusing of the metal) are found here. To
understand how iron and limestone formed in this long belt,
envision the landscape as it appeared between 200 million and 540
million years ago. During that time, much of what is now the United
States was covered by a vast, shallow sea. Shells and hard parts of
ancient marine animals and plants fell to the bottom of this sea
and accumulated to form deposits that later became limestone
(calcium carbonate).
Taken from: Geologic Wonders of the George Washington and
Jefferson National Forests No. 3 in a Series U.S. Department of
Interior
U.S. Geological Survey in cooperation with U.S. Department of
Agriculture Forest Service, Southern Region
When you visit Big Gem Park you will no longer see any exploits
of the furnace, but rather an enjoyable recreational area with a
pond for fishing and other activities. A fishing license is
necessary.
To log this cache
1.take a picture of you or your gps and the pond in the
background.
2. There are three ways iron ore deposits are identified.
Looking at the surroundings and in particular the rocks across the
pond, how do you think iron ore is presented in this area? Banded
Iron Deposits, Magmatic Magnetite Ore Deposits, or Hematite Ore.
You may need to do a little research to figure out the answer.
3.Why do you think the color of the water is as such?
4. From the coordinates, looking across the pond (facing N NE)
you will notice the area lined with boulders. You will also notice
some different colored bands in those boulders. What color are
those bands and estimate the range of thickness in height of the
band?
Email me the answers to these questions. PLEASE DO NOT
POST ANSWERS in your log: